Optical QSFP Transceiver BlueOptics BO25K859S3D 40GBASE-ESR4 Multimode Fiber

BlueOptics BO25K859S3D is a QSFP optical transceiver module engineered for 40GBASE-ESR4 multimode fiber links. It occupies a compact QSFP form factor and supports four parallel lanes to deliver aggregate 40 Gbit/s throughput for short-reach multimode applications. The module is intended for use in data center and enterprise aggregation, switch-to-switch uplinks, and high-density fiber patch deployments where reliable, hot-pluggable 40 Gb/s connectivity is required.

Advantages

The transceiver offers a compact QSFP design that enables high port density in switches and routers, while supporting multimode fiber to keep link costs and cabling complexity lower for short distances. Hot-pluggable operation simplifies installation and replacement without powering down equipment. Designed for 40GBASE-ESR4 operation, it provides stable aggregate throughput across the four parallel lanes and is compatible with common multimode fiber cabling practices used in datacenter environments.

Suitable for

• Data center switch-to-switch uplinks and aggregation
• High-density server or switch port expansion
• Short-reach multimode fiber links within campus or enterprise networks
• Fiber patch panels and optical distribution in rack deployments

Key specifications

• Form factor: QSFP (Quad Small Form-factor Pluggable)
• Data rate: 40 Gbit/s aggregate (four lanes)
• Standard: 40GBASE-ESR4 for multimode fiber
• Fiber type: Multimode fiber (OM3/OM4 compatible for short reaches)
• Distance: short-reach multimode links (designed for intra-data-center distances)
• Connector: MPO/MTP-style parallel fiber interface
• Hot-pluggable: yes

How to use

Insert the QSFP transceiver into a compatible QSFP port on a switch or router until it seats firmly; avoid excessive force. Connect an MPO/MTP parallel multimode fiber cable between the transceiver and the remote device or patch panel, ensuring correct fiber polarity and that the fiber type (OM3/OM4) matches the intended distance. After physical installation, verify link status in the host device management interface and ensure the port speed and lane configuration are set for 40GBASE-ESR4 operation. Handle the module by its edges and keep dust caps on fiber connectors when not in use to prevent contamination.

Usage recommendations

Use this QSFP transceiver with high-quality OM3 or OM4 multimode fiber and MPO/MTP trunk cables for reliable short-reach 40G links. Ensure proper cable polarity and cleanliness during installation, and confirm compatibility with the host equipment's QSFP interface and firmware to avoid interoperability issues.